We propose to measure regional effects on dopamine (DA) metabolism produced by chronic administration of antipsychotic drugs (APD) to animals. Four groups of experiments are proposed: (1) fluorometric measurement of regional HVA and DOPAC following acute and chronic administration of APD to rabbits; (2) measurement of regional HVA and DOPAC and measurement of catalepsy following chronic APD administration to rats; (3) measurement of regional AC-Ch levels during and following chronic APD administration to rats; (4) measurement of CSF cyclic AMP in rabbits following chronic APD administration (animals in experiment (1)). By these experiments we hope to test further the "dopamine hypothesis" as it relates to the mechanism and site of action of APD. BIBLIOGRAPHIC REFERENCES: Bowers, M. B., Jr. and Rozitis, A.: Brain homovanillic acid: regional changes over time with antipsychotic drugs. Eur J Pharmacol 39:109-115, 1976. Bowers, M. B., Jr. and Rozitis, A.: Brain homovanillic acid: regional changes following chronic antipsychotic drug administration. In: E. Costa and G. L. Gessa, eds. Advances in Biochemical Psychopharmacology Vol. 16. New York: Raven Press, 1977 (in press).